media/fft/fft-real-pair.h

   1 /*
   2  Free FFT and convolution (C)
   3
   4  Copyright (c) 2020 Project Nayuki. (MIT License)
   5  https://www.nayuki.io/page/free-small-fft-in-multiple-languages
   6
   7  Permission is hereby granted, free of charge, to any person obtaining a copy of
   8  this software and associated documentation files (the "Software"), to deal in
   9  the Software without restriction, including without limitation the rights to
  10  use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  copies of the Software, and to permit persons to whom the Software is
  12  furnished to do so, subject to the following conditions:
  13  - The above copyright notice and this permission notice shall be included in
  14    all copies or substantial portions of the Software.
  15  - The Software is provided "as is", without warranty of any kind, express or
  16    implied, including but not limited to the warranties of merchantability,
  17    fitness for a particular purpose and noninfringement. In no event shall
  18    the authors or copyright holders be liable for any claim, damages or
  19    other liability, whether in an action of contract, tort or otherwise,
  20    arising from, out of or in connection with the Software or the use
  21    or other dealings in the Software.
  22 */
  23
  24 #include <stdbool.h>
  25 #include <stddef.h>
  26
  27
  28 #ifdef __cplusplus
  29 extern "C" {
  30 #endif
  31
  32
  33 /*
  34  Computes the discrete Fourier transform (DFT) of the given complex
  35  vector, storing the result back into the vector.  The vector can have
  36  any length. This is a wrapper function. Returns true if successful,
  37  false otherwise (out of memory).
  38 */
  39 bool Fft_transform(float real[], float imag[], size_t n);
  40
  41
  42 /*
  43  Computes the inverse discrete Fourier transform (IDFT) of the given
  44  complex vector, storing the result back into the vector.  The vector
  45  can have any length. This is a wrapper function. This transform does
  46  not perform scaling, so the inverse is not a true inverse.  Returns true
  47  if successful, false otherwise (out of memory).
  48 */
  49 bool Fft_inverseTransform(float real[], float imag[], size_t n);
  50
  51
  52 /*
  53  Computes the discrete Fourier transform (DFT) of the given complex
  54  vector, storing the result back into the vector.  The vector's length
  55  must be a power of 2. Uses the Cooley-Tukey decimation-in-time radix-2
  56  algorithm.
  57  Returns true if successful, false otherwise (n is not a
  58  power of 2, or out of memory).
  59 */
  60 bool Fft_transformRadix2(float real[], float imag[], size_t n);
  61
  62
  63 #ifdef __cplusplus
  64 }
  65 #endif